1. Field of the Invention
This invention relates to apparatus for grinding fuel preparatory to its delivery to a boiler or other point of use.
2. Description of the Prior Art
The most pertinent prior art is represented by the prior U.S. Pat. No. of Williams 4,184,640 of Jan. 22, 1980 and certain of the references, such as Williams, U.S. Pat. No. 3,337,142 of Aug. 22, 1967, Williams, U.S. Pat. No. 4,022,387 of May 10, 1977, and Dickey, U.S. Pat. No. 2,172,317 of Sept. 5, 1939.
In the Williams U.S. Pat. No. 4,184,640, the disclosure relates to operating the apparatus to maintain a fuel rate dependent on mill speed and consistent with boiler demand. The fuel rate is arrived at by varying the mill speed and the classifier speed inversely, while the air moving fan adjustment maintains a coal-to-air ratio suitable for the burner being supplied.